Autotransformer



Jan. 23, 1968 C. B. VAUGHAN 3.355.685 i AUTOTRANSFORMER Original Filed Jan. 15, 1962 United States Patent 3,365,635 AUT'IRANSFRMER Carroll B. Vaughan, East Orange, NJ., assigner to The Bendix Corporation, a corporation of Delaware Application Aug. 6, 1963, Ser. No. 300,312, now Patent f The present application is a division of U.S. application Ser. No. 300,312, filed Aug. 6, 1963, by Carroll B. Vaughan, now U.S. Patent No. 3,263,195, granted July 26, 1966 and filed with a U.S. application Ser. No. 300,317, filed-Aug. 6, 1963 by Carroll B. Vaughan, now U.S. Patent No. 3,247,445, granted April 19, 1966, both of said applications Ser. No. 300,312 and Ser. No. 300,317 being filed as a division of a U.S. application Ser. No. 166,224, filed lan. 15, 1962 by Carroll B. Vaughan, now U.S. Patent No. 3,254,291, granted May 31, 1966, and assigned to The Bendix Corporation and the invention relates in general to an autotransformer and more particularly to a multi-tap auto transformer having a plurality of independently variable output terminals.

Heretofore, a number of devices were available to supply from a single alternating current source, a plurality of independently adjustable alternating currents on a plurality of channels. These devices used a separate auto transformer for each output channel. Or, if there was a predetermined relationship between the alternating currents to be provided at two channels, a single auto transformer was used, with two brushes mechanically linked together.

The present invention is a multi-independent brush auto transformer that provides a plurality of independently adjustable alternating currents on a plurality of channels with the use of only a single magnetic core and a single source of alternating current. Some of the advantages of the novel multi-independent brush auto transformers are compactness, eiliciency, and the ability to avoid saturation of the core when the output voltage is half wave rectied.

The ability to avoid saturation of the magnetic core is inherent to the multi-tap auto transformers. Saturation occurs when the output of an auto transformer feeds a half wave load. However, the multi-tap auto transformer can feed several half wave loads, one on each of its output terminals. The half wave loads can be adjusted so that the loads at some terminals will be of one polarity while the load at the other terminals will be of the other polarity, thus avoiding saturation of the magnetic core.

An object of the invention is in the provision of a novel multi-channel power supply.

Another object of the invention is in the provision of a novel multiple tap auto transformer having several output channels, each output voltage being independently adjustable.

Another object of the present invention is in the provision of a novel alternating current power supply having a multiplicity of output terminals; the voltage at each terminal being continuously adjustable and adjustable independently of each other.

Another object of the invention is in the provision of a novel alternating current power supply having a plurality of independently adjustable output voltages taken oil a single core auto transformer.

Another object of the present invention is in the provision of a novel auto transformer having a plurality of independently adjustable output terminals to provide a compact alternating current power supply.

Another object of the invention is to provide a novel independent brush auto transformer having a plurality ICC of output terminals to avoid saturation of the core during half wave loading of the outputs.

These and other objects and features of the invention are pointed out in the following description in terms of the embodiment thereof which is shown in the accompanying drawings. It is to be understood, however, that the drawings are for the purpose of illustration only and are not a definition of the limits of the invention, reference being had to the appended claims for this purpose.

FIGURE 1 is a side View of a multi variable brush auto transformer embodying the present invention.

FIGURE 2 is an end view of one of the single brush assemblies with the brush assembly being adjusted from a position such as shown in FIGURE 1 to a 330 degree position adjacent a mounting frame.

The present invention relates to a novel multi independent brush auto transformer (or alternating current power supply, one embodiment of which is shown by FIGURES 1 and 2).

Referring to FIGURE 1, there is shown thereby a side View of the operative parts of the novel multi-independent brush auto transformer. In particular, a toroid 201 is wound with a wire in a single layer over its outside cylindrical surface so as to provide an exposed segmental wire contact or commutator surface 203 of a wire wound toroid, as described and claimed in a copending U.S. application Ser. No. 315,735, filed Sept. 25, 1965, by Carrol B. Vaughan, now U.S. Patent No. 3,243,751, granted Mar. 29, 1966, and tiled as a division of U.S. application Ser. No. 166,343, filed Ian. 15, 1962, by Carroll Byrd Vaughan, now U.S. Patent No. 3,213,520, granted Oct. 26, 1965 to Carroll B. Vaughan for Method for vPreparing a Toroid Core, and assigned to The Bendix Corporation, assignee of the present application. Two ends of the wire wound toroid 201 may be brought out to suitable terminaison a toroid frame (not shown) and connected to a suitable source of alternating current (not shown).

The toroid 201 is rigidly mounted on a shaft 247 which is mounted on a frame 248 by two brackets 249 and 249A. A suitable flange or spacer 246 =which may be of a suitable electrical insulating material is mounted at one end of the toroid 201 and separates that end of the toroid 201 from the bracket 249 while the opposite end of the toroid 201 is positioned in spaced relation to the bracket 249A. Six adjustors comprising six knurled wheels 250a through 250i are rotatably mounted on the shaft 247 and coaxial with the toroid 201. Six arms, 251a through 2511 of conducting material, are securely mounted in a conventional manner one each to the knurled wheels 250.1 through 250]c of a suitable electrical insulating material, and the wheels 250:1 through 2501* are so spaced that the arms can pass each other freely. Six brush holder assem- .blies 252a through 252f are mounted at the ends of arms 251a through 251f and each contains a brush 2530 through 2531. Each brush 253a through 253f makes an operative electrical Contact with a wire commutator snrface 203 (or segmental surfaces of the wire winding) of the toroid 201, with each brush making contact along a different path or track on the wire wound commutator surface 203. The Wire wound surface 203 may be, for example, of a commutator type.

Six electrical conductors 255a through 255]t connect each conducting arm 251a through 251]t to six hair springs 256a through 256i, made of conducting material. Each spring is made of, for example, phosphor bronze ribbon and is enclosed in a spaghetti sleeving 258 of a suitable electrical insulating material, as shown in FIGURES 1 and 2. The enclosed springs 256:1 through 256)c are coiled around the shaft 247 next to the associated wheel 25011 through 250]c to form a one and one quarter turn loop around the shaft when the brush 253 is rotated to. for example, a three hundred and thirty degree position as shown by FIGURE 2; and a half open turn when the brush is in a zero degree position. The purpose of the phosphor ribbon conductor is twofold: first, to mechanically standup under constant coiling and uncoiling, caused by the wheel 250 turning in adjustment of the output voltage; and second, to be a conductor from the brush 253 (in contact with the contact surface 203) to terminal 259 on the frame that will not interfere with the independent motion of the wheels 250.

The other end of each spring ribbon 256a through 256f is connected to terminals 259:1 through 259f on the frame 248. Thus, a multi-tap independently variable auto transformer is constructed. The number of independent variable taps will depend on the width of the toroid 201 and the number of knurled wheels 250 with attached arm 253 and brush 257.

Each of the knurled vwheels 250a through 250] have a portion thereof extending through a slot in the frame 148 and such portion of the wheels may bear suitable indicia 260a through 26W, respectively. Such indicia may be viewable on the portion extending through the slot inthe frame 148 so as to indicate the relative position of each brush 253 with respect to the wire wound commutator surface 203 and from, for example, the zero degree position to the three hundred and thirty degree position.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art may be made without departing from the scoping of the invention. Reference is, therefore, to be had to the appended claims for a delini tion of the limits of the invention.

What is claimed is:

1. A multiple tap auto transformer comprising a toroidal core of magnetic material, a wire winding on said core and including commutator type portions thereof, a plurality of brushes for contacting said commutator portions of said winding, a frame, a shaft supported by said frame, and said core mounted on said shaft, a plurality of wheels rotatably mounted on the shaft, each of said wheels including an extension arm mounting a brush therein, each extension arm including electrical conducting means connected to the brush mounted in said extend sion arm, said wheels and arms being so adapted that the brushes can pass each other while in Contact with the commutator portions of said winding, and a plurality of electrical conductors connected to the conducting means and of a resilient material adapted to be coiled about the shaft as the wheels are rotated.

2. The combination defined by claim 1 in which each of the plurality of electrical conductors includes a hair spring ribbon, an electrical insulating sleeve enclosing each of the hair spring ribbons, each of said hair spring ribbons and insulating sleeves having one of said wheels associated therewith and being coiled around the shaft in a position adjacent the wheel associated therewith, terminals mounted on the frame, each of said terminals being connected to an end of one of said spring ribbons, and another end of each of said spring ribbons being connected to the conducting means of the extension arm of the wheel associated therewith.

3. The combination defined by claim l in which said frame includes slot means, each of said lwheels includes a portion extending through said slot means, and indicia on said portion of the wheel to indicate the position of the brush associated with said wheel in relation to the commutator portions of said winding.

4. The combination dened by claim 3 in which each of the plurality of electrical conductors includes a phosphor bronze hair spring ribbon, an electrical insulating sleeve enclosing each of the hair spring ribbons, each of said hair spring ribbons and insulating sleeves having one of said wheels associated therewith and being coiled around the shaft in a position adjacent the wheel associated therewith. terminals mounted on the frame, each of said terminals being connected to an end of one olf said spring ribbons, and another end of each of said spring ribbons being connected to the conducting means of the extension arm of the Wheel associated therewith.

References Cited FOREIGN PATENTS 263,829 7/1927 Great Britain.

LEWIS H. MYERS, Primary Examiner. D. A. TONE, Assistant Examiner. 

1. A MULTIPLE TAP AUTO TRANSFORMER COMPRISING A TOROIDAL CORE OF MAGNETIC MATERIAL, A WIRE WINDING ON SAID CORE AND INDLUDING COMMUTATOR TYPE PORTIONS THEREOF, A PLURALITY OF BRUSHES FOR CONTACTING SAID COMMUTATOR PORTIONS OF SAID WINDING, A FRAME, A SHAFT SUPPORTED BY SAID FRAME, AND SAID CORE MOUNTED ON SAID SHAFT, A PLURALITY OF WHEELS ROTATABLY MOUNTED ON THE SHAFT, EACH OF SAID WHEELS INCLUDING AN EXTENSION ARM MOUNTING A BRUSH THEREIN, EACH EXTENSION ARM INCLUDING ELECTRICAL CONDUCTING MEANS CONNECTED TO THE BRUSH MOUNTED IN SAID EXTENSION ARM, SAID WHEELS AND ARMS BEING SO ADAPTED THAT THE BRUSHES CAN PASS EACH OTHER WHILE IN CONTACT WITH THE COMMUTOR PORTIONS OF SAID WINDING, AND A PLURALITY OF ELECTRICAL CONDUCTORS CONNECTED TO THE CONDUCTING MEANS AND OF A RESILIENT MATERIAL ADAPTED TO BE COILED ABOUT THE SHAFT AS THE WHEELS ARE ROTATED. 